In my Muppet fan experience for the past 29 years, I have always found the main 5 to be just about the same. Kermit, Miss Piggy, Fozzie, Gonzo and Animal. But I always looked at is more as the big 7 including Scooter and Rowlf. If anything Rowlf and Animal were on equal merchandise footing.
Since the death of Hunt and Henson, Rowlf and Scooter have moved to the background. Neither were featured more or less than Animal in GMC or MTM.
I can't stand it when fans suggest Henson should pull new popular characters to give classic ones more screen time. Ultimately they have to use what works for today's audiences. That doesn't mean that Rowlf should have less of a role than Pepe. It simply means that he should have more of one without having to send Pepe into the background. It's not an all or nothing proposition.
I was very pleased that Scooter received a substancial part in the Christmas special. I hope we'll be seeing more of him and Rowlf. They are both personal faves of mine. I'd like to see more Mayhem too.
I find it funny how Beaker has become such a break-away icon these days. To me, there's a big 8 these days: Kermit, Animal, Gonzo, Piggy, Beaker, Fozzie, Rizzo and Pepe in about that order. That doesn't mean the others are unpopular, but these are the ones Henson appears to be pushing.
There's room enough in Muppetdom for all.